The present invention relates to an apparatus for securing a toolholder within a base and, more specifically, relates to the use of a cam mechanism for manipulating a lock rod to secure a toolholder within a base.
As an overview, metalworking operations are typically performed using a cutting insert of a hard metal. Such an insert is mounted to a toolholder. The toolholder is secured either temporarily or permanently to a base member which is part of a machine such as a lathe or a milling machine.
Because of the extreme conditions under which they operate, cutting inserts must be replaced on a regular basis. In order to do this, the cutting insert must be removed from the toolholder. The economies of the metalworking operation make it inefficient to shut a machine down for the length of time required to replace a cutting insert on a toolholder. It is more desirable to utilize a removable toolholder such that the entire toolholder with the accompanying cutting insert may be removed and replaced with another toolholder having a new cutting insert already in position on the toolholder.
With this in mind, the focus for efficiency then becomes the ease and speed with which the toolholder may be replaced. This has been one of the motivating factors producing different commercial designs for quick change toolholders.
One example of such a design may be found in U.S. Pat. No. 4,747,735 entitled "Toolholder and Method of Releasably Mounting" by Erickson et al. which is assigned to the applicant of the subject invention and which is hereby incorporated by reference. This reference teaches a spring loaded reciprocating lock rod which is urged rearwardly by the springs to move locking members radially outwardly to secure a toolholder within the toolholder support member. In order to release the toolholder, the lock rod must be advanced against the spring force so that the locking members are retracted and, furthermore, so that the toolholder is bumped from the toolholder support member. The locking mechanism described in this patent must be activated axially and is not capable of side activation.